The present invention relates to hand applicators for installing radially assembled spring retaining rings and, in particular, for installing radially assembled spring retaining rings into external grooves of workpieces.
Radially assembled spring retaining rings, such as the type disclosed in Wurzel U.S. Pat. No. 3,595,123 issued July 27, 1971, have long been employed as stop or limiting elements on machined parts. Retaining rings of this type are installed in external grooves formed in the parts. Externally applied retaining rings are installed in external grooves by pushing the open side of the ring against the groove, causing the ring ends to separate. When the thus-expanded ring has fully entered the groove, the ring ends snap-back to secure the ring in place.
In order to facilitate the installation of radially applied rings, it has been proposed to employ a hand applicator which forcefully inserts a ring into a groove of a machine part. Hand-held applicators have been proposed, for example, in Erdman U.S. Pat. No. 2,978,802 issued Apr. 11, 1961 and Janecka U.S. Pat. No. 3,681,839 issued Aug. 8, 1972.
In addition, the assignee of the present invention has heretofore marketed an applicator which comprises a hand-held housing on which is mounted a magazine and a nose assembly. The nose assembly contains a ramp along which retaining rings can be pushed, and a forwardly open slot for receiving a workpiece such as a shaft, the width of the slot being equal to the diameter of the shaft. The magazine feeds retaining rings to the ramp one-at-a-time. The housing carries a pusher and a fluid-driven mechanism for reciprocating the pusher when the user activates a trigger on the housing. When the pusher travels forwardly, it pushes a retaining ring into a groove on the workpiece. It can occur, however, that the groove is not properly aligned with the ramp, whereupon the ring can be installed in a skewed condition, i.e., partly in the groove and partly out of the groove. Such an improper installation, if not detected, may lead to failure. Even if the improper installation is detected, correction thereof is inconvenient and time-consuming on an assembly line where delays are not easily tolerated.
In the above-mentioned Janecka and Erdman patents, a groove locator finger is provided such that the locator finger passes through the workpiece groove as the workpiece is being received in a slot of the applicator. This is intended to align the groove with a retaining ring located in the slot. Thus, as the applicator continues to be advanced relative to the workpiece, the locator finger moves out of the groove and thereafter the retaining ring is pushed into the vacated groove. The locator finger of the Erdman patent is made yieldable so as to be able to yield outwardly when the shaft and installed ring are removed from the slot (see FIGS. 8-11 of the Erdman patent).
In order for the applicators of the above-described type to function acceptably, the manipulation of the applicators must be performed in such a manner that the groove and retaining ring do not become misaligned during the instant after the locator finger leaves the groove and before the retaining ring enters the groove. Otherwise, the ring could become installed in a skewed fashion.
In commonly assigned copending Application Ser. No. 06/579,559 of Edmund F. Killian filed Feb. 13, 1984, a hand applicator is disclosed in which one or more pivotably mounted locators are provided near the end of the ramp. The locator is spring-biased toward the slot in the ramp so as to be receivable in the workpiece groove. A cam face is disposed on a rear side of each locator forwardly of the pivot axis and is adapted to be engaged by a ring as the ring is being pushed by the pusher. As a result, the ring cams the locators outwardly as the ring enters the workpiece. The disclosure of that application is incorporated herein by reference. Such an arrangement provides a highly effective and dependable means of accurately inserting a retaining ring into a workpiece groove. However, room for improvement remains. In that regard, it will be appreciated that as the legs of the ring apply laterally outward forces against the cam faces of the locators, the resulting reaction forces acting against the ring legs will tend to close the ring, i.e., to force the legs of the ring together. This closing action makes it more difficult to install the ring in the workpiece groove. Thus, it would be desirable to minimize the forces tending to close the ring.
Furthermore, it may occur that the forces acting upon the ring cause the ring to be slightly raised off the ramp floor as the ring approaches the workpiece groove. If the thickness of the ring has been designed to closely match the thickness of the workpiece groove, such raising of the ring may produce sufficient misalignment between the ring and groove (e.g., the plane of the ring becomes slightly skewed relative to the plane of the groove) to prevent the ring from entering the groove. Therefore, it could be desirable to prevent such misalignment.
It is, therefore, an object of the present invention to minimize or obviate problems of the type discussed above.
Another object is to provide a novel applicator for installing retaining rings into external grooves of workpieces.
A further object is to provide such an applicator which includes locators for automatically locating the applicator relative to the workpiece groove, wherein the tendency for the locators to compress or close the spring is minimized.
An additional object is to assure that the rings are held against the floor of the ramp as they approach the workpiece groove, in order to minimize any tendency for the rings to become misaligned relative to the groove.